遍历HashMap集合

 第一种:

Map map = new HashMap();

Iterator iter = map.entrySet().iterator();

while (iter.hasNext())

{ Map.Entry entry = (Map.Entry) iter.next();

Object key = entry.getKey();

Object val = entry.getValue();

}

效率高,以后一定要使用此种方式！

 第二种:

Map map = new HashMap();

 Iterator iter = map.keySet().iterator();

while (iter.hasNext()){

Object key = iter.next();

Object val = map.get(key);

}

效率低,以后尽量少使用

//map的遍历方法3
Iterator it = map.keySet().iterator();
while(it.hasNext()){
System.out.println(map.get(it.next()));
}
//map的遍历方法4
// Iterator it = map.values().iterator();
// while(it.hasNext()){
// String val = (String)it.next();
// System.out.println(val);
// }